Method and apparatus for peeling a thin film from a liner

ABSTRACT

A method and apparatus are provided for peeling a thin film, typically 100 microns or less in thickness, from a liner by use of a rotatable peel rod supported in an air bearing. The air bearing comprises a support plate having arcuate surfaces which are substantially coaxial with a cylindrical film-bearing segment of the peel rod. Air openings in the arcuate surfaces conduct a flow of air into an air bearing gap between the arcuate surfaces and the peel rod.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.10/959,848, filed Oct. 6, 2004, now allowed, which was a divisional ofU.S. application Ser. No. 10/115,778, filed Apr. 3, 2002, issued as U.S.Pat. No. 6,868,890, the disclosure of which is herein incorporated byreference.

FIELD OF THE INVENTION

This invention relates to a method and apparatus for peeling a thinfilm, typically 100 microns or less in thickness, from a liner by use ofa rotatable peel rod supported in an air bearing.

BACKGROUND OF THE INVENTION

U.S. Pats. Nos. 5,556,499 and 5,762,753 disclose a peeler-delaminatormethod and apparatus employing a peel bar supported in a solid bearingthat provides continuous bearing contact with the peel bar. Thereferences also describe a peel bar bearing that includes an abrasivesurface for continuously scrubbing the peel bar.

SUMMARY OF THE INVENTION

Briefly, the present invention provides an apparatus for removing a filmfrom a liner that includes a rotatable peel rod supported in an airbearing. The air bearing comprises a support plate having arcuatesurfaces which are substantially coaxial with a cylindrical film-bearingsegment of the peel rod. Air openings in the arcuate surfaces conduct aflow of air into an air bearing gap between the arcuate surfaces and thepeel rod.

In another aspect, the present invention provides a method for removinga film from a liner comprising the steps of passing a bilayer of a filmand a liner over a rotatable peel rod supported in an air bearing, suchthat the film contacts the peel rod, and peeling the film from theliner. The film typically has a thickness of 100 microns or less.

What has not been described in the art, and is provided by the presentinvention, is a method and apparatus that employs a rotatable peel rodsupported in an air bearing to peel a delicate or thin film from aliner.

It is an advantage of the present invention to provide a method andapparatus that facilitates the use of rolls of thin cast film in anautomated manufacturing process.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates a peeling mechanism according to the presentinvention.

FIG. 2 is a cross-section of the peeling mechanism depicted in FIG. 1.

FIG. 3 is a detail of FIG. 2 demonstrating the peel rod according to thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIGS. 1, 2 and 3, a peeling apparatus according to thepresent invention comprises frame members 10, 11, 12 and 13, whichtogether form a supporting frame. Peel rod support plate 40 is attachedto one or more of frame members 10, 11 and 12. Peel rod support plate 40comprises arcuate surfaces 41 and 42 for receiving peel rod 50. Peel rod50 is essentially cylindrical in its film-bearing middle segment. Peelrod 50 may be essentially cylindrical throughout it's length, or mayhave non-cylindrical end segments such as rounded ends or otheradaptations for interaction with end caps 60 and 61. End caps 60 and 61prevent escape of peel rod 50, which might otherwise occur either bytransverse motion of peel rod 50, or by the absence of film 90, whichmight occur, e.g., at the end of a run. End caps 60 and 61 may comprisebearings for each end of peel rod 50, such as a needle bearings. Endcaps 60 and 61 may be attached to frame members 11 and 12 or to peel rodsupport plate 40, or to both. Where end caps 60 and 61 comprise bearingsfor each end of peel rod 50, end caps 60 and 61 may be attached to framemembers 11 and 12 or to peel rod support plate 40 by a slidingattachment allowing motion of peel rod 50 closer or farther from airbearing gaps 51 and 52.

The curve of each arcuate surface 41 and 42 is substantially coaxialwith the curve of the essentially cylindrical film-bearing middlesegment of peel rod 50. In use, air bearing gaps 51 and 52 separatearcuate surfaces 41 and 42 from peel rod 50. Air is driven into airbearing gaps 51 and 52 through air openings, which may comprise a groove43 separating arcuate surfaces 41 and 42, the groove 43 traversingsubstantially the entire length of the air bearing gap 51, 52 along thelength of the film-bearing segment of peel rod 50. In anotherembodiment, the air openings might comprise a series of holes. Thegroove 43 or other air openings are fed by one or more air channels 44,which in turn are fed by air channels 101, 102 in manifold block 100attached to peel rod support plate 40. Any suitable source ofsuper-ambient air pressure may be used to feed air channels 44, 101,102, such as an air pump. Any suitable level of air pressure or anysuitable air flow rate may be used, provided that a suitable air bearinggap is maintained during operation.

Liner support roller 30 and film idler roll 20 are rotatably attached toframe members 11 and 12. Liner support roller 30 is positioned adjacentto peel rod 50 so as to form a nip. Film idler roll 20 is positioned soas to receive film 90 passing over peel rod 50 and maintain film 90 in astable orientation relative to peel rod 50.

In operation, a bilayer 70 which comprises a liner 80 bearing a film 90is directed into the nip formed by liner support roller 30 and peel rod50. While liner 80 maintains contact with liner support roller 30, film90 is peeled from liner 80 and follows the surface of peel rod 50. Peelrod 50 rotates as film 90 passes over peel rod 50. Film idler roll 20receives film 90 passing over peel rod 50 and maintains film 90 in astable orientation and tension relative to peel rod 50. Typically, thepresent apparatus is driven by a pulling force applied to a liner 80 byany suitable drive means. In addition, liner support roller 30 may alsobe driven.

The method according to the present invention is used to advantage withdelicate or thin films. Typically, the present method may be used topeel films of 100 micrometers thickness or less, more typically 50micrometers thickness or less, and more typically 30 micrometersthickness or less. The method according to the present invention may beused to advantage with films of polymer electrolyte membranes that arecast on a liner, including sulfonated fluoropolymer membranes such asNafion™ or Flemion™. Any suitable liner may be used, including anysuitably flexible polymeric sheet materials having a thickness oftypically less than 1 millimeter, more typically less than 0.5millimeter, and more typically less than 0.2 millimeter. Films may becast from a solution or suspension of the film polymer by any suitablemethod, including coating or casting methods including bar coating,spray coating, slit coating, brush coating, and the like. Since the castfilm may have uneven edges, the cast film may be cut on one or moreedges to provide a clean edge. Typically, a continuous web of cast filmcan be die cut to provide clean side edges using controlled-depth diecutter.

This invention is useful in the manufacture of goods, such as membraneelectrode assemblies used in fuel cells, from membranes of polymerelectrolytes that are cast on a liner as thin films of 30 micrometerthickness or less.

Various modifications and alterations of this invention will becomeapparent to those skilled in the art without departing from the scopeand principles of this invention, and it should be understood that thisinvention is not to be unduly limited to the illustrative embodimentsset forth hereinabove. All publications and patents are hereinincorporated by reference to the same extent as if each individualpublication or patent was specifically and individually indicated to beincorporated by reference.

1. An apparatus for removing a film from a liner comprising a rotatablepeel rod supported in an air bearing.
 2. The apparatus according toclaim 1 wherein said peel rod comprises a film-bearing segment which isessentially cylindrical and has a center axis, and wherein said airbearing comprises a support plate having one or more arcuate surfaceswhich are substantially coaxial with said film-bearing segment of saidpeel rod, said support plate comprising one or more air openings in saidarcuate surfaces for conducting a flow of air into an air bearing gapbetween said arcuate surfaces and said film-bearing segment of said peelrod.
 3. The apparatus according to claim 2 additionally comprising asource of super-ambient air pressure functionally connected to said airopenings so as to provide a flow of air into said air bearing gap. 4.The apparatus according to claim 3 wherein said air openings comprise agroove in said arcuate surface traversing substantially the entirelength of said air bearing gap.
 5. The apparatus according to claim 4additionally comprising a liner support roller positioned adjacent tosaid peel rod so as to form a nip.
 6. The apparatus according to claim 5additionally comprising a film idler roll positioned so as to receive afilm passing over said peel rod and maintain said film in a stableorientation relative to said peel rod.
 7. The apparatus according toclaim 6 additionally comprising a frame to which said film idler roll isrotatably attached, to which said liner support roller is rotatablyattached, and to which said support plate is fixedly attached.
 8. Amethod for removing a film from a liner comprising the steps of: passinga bilayer of a film and a liner over a rotatable peel rod supported inan air bearing such that said film contacts said peel rod; and peelingsaid film from said liner.
 9. The method according to claim 8 whereinsaid peel rod comprises a film-bearing segment which is essentiallycylindrical and has a center axis, and wherein said air bearingcomprises a support plate having one or more arcuate surfaces which aresubstantially coaxial with said film-bearing segment of said peel rod,said support plate comprising one or more air openings in said arcuatesurfaces for conducting a flow of air into an air bearing gap betweensaid arcuate surfaces and said film-bearing segment of said peel rod.10. The method according to claim 9, wherein said air openings comprisea groove in said arcuate surfaces traversing substantially the entirelength of said air bearing gap.
 11. The method according to claim 10,wherein said air openings are functionally connected to a source ofsuper-ambient air pressure such that a flow of air into said air bearinggap is provided.
 12. The method according to claim 11 wherein said stepof passing a bilayer of a film and a liner over a rotatable peel rodcomprises passing said bilayer into a nip formed between said peel rodand a liner support roller positioned adjacent to said peel rod.
 13. Themethod according to claim 12, wherein contact is maintained between saidliner and said liner support roller during said peeling step.
 14. Themethod according to claim 13 additionally comprising the step of passingsaid film peeled from said liner over a film idler roll positioned so asto maintain said film in a stable orientation relative to said peel rodduring said peeling step.
 15. The method according to claim 8 whereinsaid film has a thickness of 100 micrometers or less.
 16. The methodaccording to claim 9 wherein said film has a thickness of 100micrometers or less.
 17. The method according to claim 12 wherein saidfilm has a thickness of 100 micrometers or less.
 18. The methodaccording to claim 8 additionally comprising the step of casting saidfilm on said liner.
 19. The method according to claim 9 additionallycomprising the step of casting said film on said liner.
 20. The methodaccording to claim 12 additionally comprising the step of casting saidfilm on said liner.
 21. The method according to claim 18 additionallycomprising a step of cutting the cast film on one or more edges so as toprovide a clean edge prior to removing said film from said liner. 22.The method according to claim 19 additionally comprising a step ofcutting the cast film on one or more edges so as to provide a clean edgeprior to removing said film from said liner.
 23. The method according toclaim 20 additionally comprising a step of cutting the cast film on oneor more edges so as to provide a clean edge prior to removing said filmfrom said liner.
 24. The method according to claim 8 wherein said filmis a polymer electrolyte membrane.
 25. The method according to claim 9wherein said film is a polymer electrolyte membrane.
 26. The methodaccording to claim 12 wherein said film is a polymer electrolytemembrane.